Conventionally, a process for industrially producing (meth)acrylic acid by gas-phase catalytic oxidation of a (meth)acrylic acid production raw material has been known. A (meth)acrylic acid-containing gas produced by a gas-phase catalytic oxidation reaction from the (meth)acrylic acid production raw material is, for example, collected by a liquid medium or condensed to be recovered as a crude (meth)acrylic acid solution, and then, the crude (meth)acrylic acid solution is purified by a method such as distillation, diffusion, extraction, crystallization, or the like.
For example, Patent Literature 1 discloses a method for purifying crude (meth)acrylic acid by repeating crystallization multiple times. In the method disclosed in Patent Literature 1, a liquid raw material stored in a kth storage tank is crystallized and then melted, a non-crystallized residual mother liquid is transferred to a k−1th storage tank, a melt is transferred to a k+1th storage tank, and then, a liquid raw material stored in the k+1th storage tank is crystallized.